National Streamflow Statistics Program: Version History Active

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NSS Version History

(Note: Database changes are in plain text. Program changes are in italics.)

NSS/StreamStats database update - 2018-01-12 - The following corrections were made in this version:

• Arkansas (SIR 2016-5081) - updated covariance matrices for peak region B2 (affects prediction intervals, not estimates).
• Illinois (SIR 2016-5050) - adjusted URBTHE2010 coefficients in many peak regions resulting in minor adjustments to Q estimates.
• Oklahoma (SIR 2014-5134) - added Regulated equations.
• Washington (SIR 2016-5118) - replaced 2001 equations with new 2016 peak equations.

NSS/StreamStats database update - 2017-09-27 - This version of the database adds new peak flow equations for Kansas (SIR 2017-5063) and new bankfull equations for Pennsylvania and portions of Maryland (SIR 2005-5147). The following corrections were made in this version:

• Vermont (SIR 2006-5217) - changed RELRELF to RELRELff to reflect ft/ft units.
• Rhode Island (SIR 2014-5010) - turned off erroneous prediction intervals in peak flow equations.
• Montana (SIR 2015-5019F) - removed northwest region flood equations until corrections can be made.
• Washington (SIR 2016-5118) - removed 2016 peak equations and restored 2001 equations until corrections can be made.
• Illinois (SIR 2016-5050) - adjusted region 3 500-yr equation coefficient from 0.301 to 0.294 (see table 9 of report).
• Idaho (SIR 2016-5083) - adjusts all peak flow equations from regions 1 and 2 with corrections to drainage areas.

NSS/StreamStats database update - 2017-04-03 - This version of the database adds many new features and corrections as described below:

• New peak-flow equations:
  • Idaho (SIR 2016-5083)
  • Massachusetts (SIR 2016-5156)
• New low-/mean-/duration-/probability-flow equations:
  • Georgia (SIR 2017-5001)
  • New York (SIR 2014-5220)
  • Vermont (SIR 2006-5217)
• Corrections:
  • Arkansas peak-flow equations (SIR 2016-5081) modified to use BSHAPE parameter
  • Massachusetts probability-flow equations (SIR 2006-5031) modified to remove faulty prediction interval computations
  • Oregon peak-flow equations (SIR 2005-5116) modified to use BSLOPD parameter

NSS/StreamStats database update - 2017-01-06 - This version of the database adds many new features and corrections as described below:

• New peak-flow equations:
  • Arkansas equations (SIR 2016-5081)
  • Colorado equations (SIR 2016-5099)
  • Illinois Urban equations (SIR 2016-5050)
  • Washington equations (SIR 2016-5118)
• New low-/mean-/duration-flow equations:
  • Indiana (SIR 2016-5102)
  • Iowa (SIR 2016-5111)
• Corrections:
  • Montana equations from SIR 2015-5019 were split into smaller logical regions to speed batch processing in StreamStats.

NSS Program update: Version 6.1 - 2016-01-06 - This version of the program fixes previous bugs and updates the help documentation. The program now generates dual warnings if an input value has more than three significant figures and an input value is outside the applicable range. The program now handles multiple urban scenarios where previously only the last scenario entered was selectable.

NSS/StreamStats database update - 2016-04-25 - This version of the database modifies SIR 2006-5306 Navajo flood regions 8 and 11 for AZ, CO, and UT to use basin slope in ft/ft instead of basin slope in percent, matching identical changes made to NM in the 2016-04-20 database version.

NSS/StreamStats database update - 2016-04-20 - This version of the database adds many new features and corrections as described below:

• New peak-flow equations:
  • Montana (SIR 2015-5019)
  • Alaska (SIR 2016-5024)
  • Maine (SIR 2015-5049)
• New low/mean/duration-flow equations:
  • Montana (SIR 2015-5019)
  • Illinois (SIR 2014-5177)
  • Indiana (SIR 2014-5177)
  • Maine (SIR 2015-5151)
  • Minnesota (SIR 2015-5170)
• Corrections:
  • All equations in New Mexico from SIR 2008-5119, WRIR 01-4271, and SIR 2006-5306 using BSLDEM30M were modified to use BSLDEM30ff instead.
  • Region names for Alaska peak flow equations were modified.
  • Equations from Arizona SIR 2014-5211 were modified to use Contributing_Drainage_Area instead of Drainage_Area.
  • Region names were modified for zero-flow probability equations in Iowa (SIR 2012-5171).
  • Corrected errors in 7Q2 and 7Q10 equations for May in region 3 for Oregon.
  • Corrected TAU* parameters in Arkansas (SIR 2008-5065) to use units of days, not years.
  •  Changed slope units for Kansas low-flow statewide equations to match correct units from report (SIR 2004-5032 and SIR 2004-5033).
  • Expired ROI equations from North Carolina removed from database.

NSS/StreamStats database update - 2015-10-13 - This version of the database replaces peak flow equations for North Dakota (SIR 2015-5096) and adds single-variable peak-flow equations for Oklahoma Panhandle (SIR 2015-5134).

NSS/StreamStats database update - 2015-09-29 - This version of the database adds new single-variable peak-flow equations for Iowa (SIR 2015-5055), adjusts prediction error values for Rhode Island peak flow equations, corrects errors in Iowa's Southern Region low-flow equations (SIR 2012-5171), and corrects errors in Oregon low-flow equations (SIR 2005-5116).

NSS/StreamStats database update - 2015-06-12 - This version of the database adds new low-flow equations from Arkansas (SIR 2015-5031) and makes minor adjustments to Rhode Island peak-flow equations (SIR 2012-5109).

NSS/StreamStats database update - 2015-02-26 - This version of the database adds groundwater recharge equations for New Hampshire (SIR 2004-5019), low-flow equations for New York (SIR 2010-5063) and Arizona (SIR 2014-5109), rural peak equations for Arizona (SIR 2014-5211), and urban peak equations for Virginia (SIR 2014-5090). Maine peak flow equations for D50, QA, and MARD50 are corrected. Minor errors not affecting streamflow computations were corrected for Kentucky and South Dakota.

NSS/StreamStats database update - 2014-10-07 - This version of the database adds new peak equations from Missouri and new low-flow equations from Missouri and West Virginia. Kansas low-flow equations from SIR 2004-5032 were modified to prevent them from producing negative values at low flows. Minor errors not affecting streamflow computations were corrected for Tennessee, Georgia, North Carolina, South Carolina, and South Dakota.

NSS Program update: Version 6.1 - 2014-09-23 - This version of the program adds a number of new features. Report citations and html links are now displayed in the Edit Scenario window, allowing the user to quickly jump to the USGS report detailing the development and use for the selected equation set (region). The Edit Scenario window now warns the user when it has rounded input variables prior to computation. "Probability of Zero Flow" estimates are now reported with "Percent Correct" indicating what portion of stations in the study are accurately predicted by these equations.

NSS/StreamStats database update - 2014-08-06 - This version of the database adds new peak equations from Vermont and new low-flow equations from Maine. Minor errors not affecting streamflow computations were corrected for New Hampshire and Kentucky.

NSS/StreamStats database update - 2014-06-12 - This version of the database corrects errors in streamflow estimates encountered in the 2014-05-09 version of the database for the States of Florida, Iowa, Ohio, Pennsylvania, Tennessee, and Utah. For more details, please see the Known Issues link on the NSS software download page.

NSS/StreamStats database update - 2014-05-09 - This version of the database adds new peak urban streamflow equations for Georgia, North Carolina, and South Carolina. Bank-full equations are added for Kentucky, Massachusetts, and Maine. Non-peak streamflow equations are added for Kentucky, New Jersey, and Rhode Island. Standard errors of prediction are updated for Colorado non-peak equations. Kansas non-peak equations are updated to include previously unsupported subtracted terms.

NSS/StreamStats database update - 2013-08-28 - This version of the database adds new peak streamflow equations for Iowa and West Virginia and adds new non-peak streamflow equations for Indiana, Iowa, and Pennsylvania. It corrects peak flow equations in Georgia and North Carolina. It also corrects errors in non-peak equations in Arkansas, Ohio, Oregon, and Vermont and copies Maryland non-peak equations to Delaware.

NSS/StreamStats database update - 2012-11-21 - This version of the database renames peak urban stats in Alabama, adds Standard Error of Prediction to Missouri Urban equations, and adds new peak streamflow equations for California, Florida, Rhode Island, and Virginia. It also adds new urban peak-flow equations for Georgia and low-flow equations for Iowa, Ohio, Virginia, and Washington.

NSS Program update: Version 6.0 - 2012-08-03 - Adds a 64-bit Windows OS compatible installer, brings the flow-type selection to the NSS main screen, adds proper display of Standard errors and prediction intervals for urban scenarios, and improves results display format.

NSS/StreamStats database update - 2012-05-09 - This version of the database prevents negative low-flow results in Oregon, corrects errors in Region 7 peak flow prediction intervals in Illinois, removes outdated ROI equations from North Carolina, renames TAU_x variables in Arkansas, corrects BCF for New York bankfull equations, presents newer ROI routines for Tennessee, and corrects errors in Maryland low-flow equations.

NSS/StreamStats database update - 2011-03-24 - This version of the database adds new urban peak flow equations for Alabama, adds prediction intervals to Arkansas peak flow equations, and adds new low-flow equations for Kentucky. Corrections for low-flow equations from Utah SIR 2008-5230 were entered into this database, and the PK25 covariance matrix was corrected for Puerto Rico. This database should be used with NSS program version 5.1.2 as posted.

NSS/StreamStats database update - 2011-02-04 - This version of the database corrects mislabeled units in Maryland peak flow equations from AHMMD 2010 and corrects mislabeled units in Texas peak flow equations from SIR 2009-5087. This database should be used with NSS program version 5.1.2 as posted.

NSS/StreamStats database update - 2011-01-18 - This version of the database adds new peak-flow equations for Maryland, Oklahoma, and Texas. New urban peak-flow equations were added for Missouri, and new low-flow equations were added for Alaska. This database should be used with NSS program version 5.1.2 as posted.

NSS/StreamStats database update - 2010-11-15 - This version of the database adds new low-flow or flow-duration equations for Oregon, Arkansas, Tennessee, New York, Hawaii, Washington, and Ohio. Arkansas region-of-influence (ROI) equationswere removed. Errors were corrected in non-peak-flow equations for Maryland and peak-flow equations for Hawaii, Maine and Nevada. Prediction interval calculations were added for New Hampshire. This database should be used with NSS program version 5.1.2 as posted.

NSS Program update: Version 5.1.2 - 2010-11-15 - Adds the ability to filter equations by one of three types: "Peak", "Probability" (of zero flow), and "Other" (non-peak). Please go to File...Options within the program to select a flow type before using the program. Also adds the ability to display peak flow statistics with traditional recurrence interval labels or newer percent chance exceedance labels (e.g. "PK100" vs. "1% flood").

NSS/StreamStats database update - 2010-07-26 - This version of the database corrects an error in Region 3 equations for Wisconsin. Peak-flow and low-flow equations in New Hampshire are updated with prediction interval computation. New peak equations for Hawaii are updated to coincide with recent revisions. This database should be used with NSS program version 5.1 as posted. There are no changes to the program version 5.1.

NSS/StreamStats database update - 2010-06-21 - This version of the database adds new peak-flow equations for Colorado, Georgia, Hawaii, Minnesota, North Carolina, New Jersey, Oklahoma, and South Carolina. New duration equations are added for Connecticut and Oklahoma. Equation errors are corrected for mean flow equations in Ohio. This database should be used with NSS program version 5.1 as posted.

NSS Program update: Version 5.1 - 2010-06-21 - Added the ability to solve a wider range of regression equations and to weight streamflow estimates by variance. Added new functionality that will eventually result in being able to describe streamflows in terms of annual exceedance probabilities or recurrence intervals. Identified and corrected a problem with prediction interval computations.

NSS/StreamStats database update - 2009-07-20 - This version of the database adds peak flow equations from New Hampshire report SIR 2008-5206. It also includes missing PK500 estimates for Alabama and Hawaii that were mistakenly deleted in previous versions and also includes minor modifications to equations from Kentucky report WRIR 91-4097. This database should be used with NSS program version 4.0b as posted. There are no changes to the NSS program version 4.0b.

NSS/StreamStats database update - 2009-04-08 - This version of the database adds peak-flow equations for West Virginia and Oklahoma and low-flow equations for Kentucky, Utah, and West Virginia. This database should be used with NSS program version 4.0b as posted. There are no changes to the NSS program version 4.0b.

NSS/StreamStats database update - 2009-02-27 - There are no changes to the NSS program version 4.0b. This version of the database adds peak-flow equations for New Mexico and corrects some error statistics in Florida. This database should be used with NSS program version 4.0b as posted.

NSS/StreamStats database update - 2009-01-27 - There are no changes to the NSS program version 4.0b. This version of the database adds peak-flow equations for Arkansas, South Carolina, and Florida. It also adds urban peak equations for New York and updates urban equations for North Carolina's Blue Ridge and Piedmont regions. This database should be used with NSS program version 4.0b as posted.

NSS Program update: Version 4.0b - 2008/12/08 - Added the abilities to (1) handle regression equations that have a multiple explanatory variables in the exponent term; (2) incorporate logistic regression equations that are found in some low-flow reports (ie the chance of a stream having zero flow); and (3) enable computing of area-weighted prediction intervals for sites with drainage area in more than one hydrologic region. In addition there was some cleanup in the way regression equations were presented in the output report.

New peak-flow equations have been added for Alabama, Arizona, Colorado, Florida, Louisiana, New Mexico, New York, Pennsylvania, South Carolina, and Utah, including completion of Utah Region_4. New low-flow equations have been added for Florida, Hawaii, Idaho, Montana, and Tennessee. Minor corrections were made to existing equations for Alabama, Delaware, Idaho, Illinois, Indiana, Texas, and Utah, including adding the ability to do prediction intervals for Indiana flood frequency estimates.

NSS Program update: Version 4.0 - 2006/12/01 - Added the abilities to (1) solve regression equations for all types of streamflow statistics, not just flood-frequency statistics, (2) use region-of-influence regression for states where it is implemented, (3) compute 90-percent prediction intervals for estimates where methods for computing them are documented in reports.

NSS Program update: Version 4.0 – 2006/12/01 - Added the abilities to (1) solve regression equations for all types of streamflow statistics, not just flood-frequency statistics, (2) use region-of-influence regression for states where it is implemented, (3) compute 90-percent prediction intervals for estimates where methods for computing them are documented in reports.

National Flood Frequency program (NFF) Version 3.2 - 2004/12/14 - Updated the database to NFFv3.2_2004-12-14.mdb. Added new peak-flow equations for Connecticut and Kentucky. Corrected an error in the units displayed for conveyance in the Houston urban equations from in/hr to cubic feet per second. Corrected an error in the Wisconsin Area 1 equation for the 5-year recurrence interval.

National Flood Frequency program (NFF) Version 3.2 - 2004/12/14 - Updated the database to NFFv3.2_2004-12-14.mdb. Added new peak-flow equations for Connecticut and Kentucky. Corrected an error in the units displayed for conveyance in the Houston urban equations from in/hr to cubic feet per second. Corrected an error in the Wisconsin Area 1 equation for the 5-year recurrence interval.

NFF Version 3.2 - 2004/09/29 - Updated the database to NFFv3.2_2004-09-29.mdb. This database contains new peak-flow equations for Alaska, Idaho, Ohio, Tennessee, Vermont, Wisconsin, and Wyoming. Along with the new database comes the ability to display 90-percent prediction intervals with the estimates for some of the updated States.

NFF Version 3.2 – 2003/04/30 - Fixed a bug in the weighting routine that occurred when equivalent years of record were missing for the regression estimates, and a bug that occurred when the drainage area for an ungaged site was in more than one region and the regions had different sets of return intervals.

NFF Version 3.1.1 - 2003/03/28 - Fixed a bug in the weighting routine that was introduced in the version 3.1 update.

NFF Version 3.1 - 2003/02/27 - Fixed a problem with solving the national urban equations that occurred when one or more of the local rural equations were missing for the region of interest. If a rural equation, such as the 5-year flow, was missing NFF would use the flow estimate for the next available recurrence interval, such as the 10-year flow, to estimate the urban flow for the missing recurrence interval. All estimates for higher recurrence intervals would also be incorrect.

NFF Version 3.0 - 2002/10/15 - Major change in converting user interface from Microsoft DOS to Microsoft Windows and converting data base from a binary file to Microsoft Access (Note: Use of trade or product names is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey). Updates or corrections to equations for

• Alabama
• Alaska
• American Samoa
• Arizona
• Arkansas
• Colorado
• Delaware
• Georgia - rural and urban
• Hawaii
• Idaho
• Iowa
• Kansas
• Kentucky - Jefferson County urban
• Louisiana
• Maine
• Maryland

• Minnesota
• Missouri
• Nebraska
• Nevada
• New Mexico
• North Carolina - rural and urban
• Oklahoma
• Pennsylvania
• Puerto Rico
• South Carolina - rural and urban
• South Dakota
• Texas - rural
• Utah
• Virginia
• Washington
• West Virginia

NFF Version 2.0 - 1996/09/15 - A non-USGS release that added conversions between English and metric units.

NFF Version 1.4 - 1996/09/30 - NFF data base updated to amend incorrect values for:

• New Jersey--the constant 1 was removed from being added to the actual value entered for impervious cover, I
• New York--incorrect exponents and an incorrect regression constant were corrected for Region 6's 25-year and 500-year equations, respectively
• Wisconsin--the constant -2.3 was added to the data base to be applied automatically to the actual value entered for 2-year 24-hour rainfall, INTENS, for Areas 1, 3, and 5; incorrect exponents were corrected for Area 3's 5-, 25-, 50-, and 100-year equations

NFF Version 1.3 - 1996/02/14 - Corrected labeling of flood-frequency recurrence intervals for North Dakota. The equations developed for North Dakota are for the 2-, 10-, 15-, 25-, 50-, 100-, and 500-year recurrence intervals rather than the standard 2-, 5-, 10-, 25-, 50-, 100-, and 500-year intervals.

NFF Version 1.2 - 1995/06/02 - NFF data base updated to amend incorrect exponents in West Virginia's Region 6 equations for the 2-year and 10-year recurrence interval.

NFF Version 1.1 - 1994/11/21 - Initial release.

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